When a recording medium, such as a magnetic disc, an optical magnetic disk, an optical disc, or the like, is used as a device for storing user data, it is required to preliminarily execute initialization of the recording medium, that is, format before actually writing user data.
Conventionally, it has been impossible to use the device before format of the entire device is completed. Accordingly, there has been a problem in that the length of the time required for completing format is too long. Consequently, a quick format for executing an initialization processing in a background of access to the device has been used.
In the quick format, in order to allow access right after initialization, a progress status of the initialization is managed by using a bitmap or the like. Then, when access to a format uncompleted area is required, the access is processed after the area is preferentially formatted.
Herein, in a device system that has a plurality of device control apparatuses managing access to a device and in which access to the device is duplicated, it is also required to duplicate the management of the progress status of the initialization. Consequently, in a conventional quick format, an update processing of a bitmap is executed and duplication of the bitmap is executed between the device control apparatuses at a timing when initialization of an area equivalent to one bit in a bitmap is completed.
However, when considering the time required for duplication of the format progress status, the time until the format is completed becomes shorter when the number of duplication of the format progress status to be executed is low.
That is, when frequency of the duplication of the progress status is considerably higher than generation frequency of access to the device during format, the time required for the format becomes long by the duplication processing. On the other hand, when frequency of the duplication of the progress status is considerably lower than generation frequency of access to the device during format, a number of accesses are forced to wait, causing lowering of access responsiveness and occurrence of time out. Further, since generation frequency of access is not constant, it has been difficult to obtain the optimum one value as for the timing for executing duplication of the format progress status.
The disclosed technique is made in the light of the aforementioned problems, and the object is to provide to a device control apparatus, a device initialization method, and a device system which make it possible to shorten the time required for format while ensuring access performance to a device.